Denture stomatitis is a very frequent complication of the denture wearers. In this study, the relation between denture plaque and denture stomatitis was evaluated by a simplified culture (STOMASTAT). 583 patients wearing dentures (1981-1987) were selected, from 47 to 91 years old. The following results were obtained. 1. Degree of denture plaque in 583 patients was severe, moderate, and no detection: 30, 35 and 35%, respectively. 2. Grade of denture stomatitis in 583 patients was severe, moderate, and no symptom: 24, 36 and 40%, respectively. In this survey, the occurrence of denture stomatitis was about 60%. 3. The good correlation between degree of denture plaque and grade of denture stomatitis was recognized in this study. The present results suggest that denture plaque plays an etiologic role in denture stomatitis and, in daily practice, it is important to instruct denture plaque control for denture wearers.